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sum(1) General Commands Manual sum(1) NAME sum - Displays the checksum and block count of a file SYNOPSIS sum [-o|-r] [file...] The sum command reads file and calculates a 16-bit checksum and the number of blocks in the file. If the file argument is omitted, sum reads standard input. STANDARDS Interfaces documented on this reference page conform to industry stan- dards as follows: sum: XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about in- dustry standards and associated tags. OPTIONS [DIGITAL] Uses an algorithm to compute the checksum using word-by-word computation. Uses an alternate algorithm to compute the checksum (rig- orous byte-by-byte computation rather than the word-by-word computa- tion). This is the default. OPERANDS The file for which a checksum is to be computed. If this operand is omitted, standard input is used. DESCRIPTION The checksum and number of blocks are written to standard output. The sum command is generally used to determine if a file that was copied or communicated over transmission lines is an exact copy of the original. The sum command writes the space used in 512-byte units. System V Compatibility [DIGITAL] The root of the directory tree that contains the commands modified for SVID 2 compliance is specified in the file /etc/svid2_path. You can use /etc/svid2_profile as the basis for, or to include in, your /etc/svid2_profile reads /etc/svid2_path and sets the first entries in the PATH environment variable so that the modified SVID 2 commands are found first. [DIGITAL] The checksum algorithms for the default sum command and the SVID 2 compliant sum command are reversed. The SVID 2 compliant sum command uses the word-by-word algorithm by default and uses the byte- by-byte algorithm if you specify the -r option on the command line. NOTES [DIGITAL] The default algorithm is no longer the word-by-word computa- tion algorithm. It was changed to the 4.3BSD default algorithm. The algorithms used may not be portable, that is, the same checksum may not be produced for the same input on different systems. Portable applica- tions should use cksum. EXIT STATUS The following exit values are returned: Successful completion. An er- ror occurred. EXAMPLES To display the checksum of datafile and the number of blocks in this file, enter: sum datafile If the checksum of datafile is 1605 and if the file contains 3 blocks, sum displays: 1605 3 datafile ENVIRONMENT VARIABLES The following environment variables affect the execution of sum: Pro- vides a default value for the internationalization variables that are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization vari- ables contain an invalid setting, the utility behaves as if none of the variables had been defined. If set to a non-empty string value, over- rides the values of all the other internationalization variables. De- termines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi- byte characters in arguments). Determines the locale for the format and contents of diagnostic messages written to standard error. Deter- mines the location of message catalogues for the processing of LC_MES- SAGES. SEE ALSO Commands: cksum(1), wc(1) Standards: standards(5) sum(1)